Mounting hardware. Key Features: Virtually indestructible 100 percent Stainless Steel Mandrel-formed tubes tune exhaust flow for maximum torque Maximize exhaust extraction Flanges welded on both sides, then milled flat Seamless high-velocity collector Pulls exhaust and slashes backpressure Heavy 400 stainless replaces crack-prone stock piece Bolts on 1/2 inch thick flanges won't warp or flex US Patent #6,634,171 B1 50 State Compliant CARB E.O. D-161-105